Method and apparatus for latency reduction of device to device (D2D) message in a wireless communication system

ABSTRACT

A method and apparatus are disclosed for latency reduction of device-to-device message in a wireless communication system. In one embodiment, the method includes the UE receiving a grant on a first interface wherein the grant indicates resource for transmitting scheduling information and resources for data transmission on a second interface. The method also includes the UE transmitting a first scheduling information on the second interface in a first specific timing interval and transmits a second scheduling information on the second interface in a second specific timing interval, wherein the timing difference between the second specific timing and the first specific timing is indicated by the grant, and wherein the first scheduling information indicates a first timing offset between the first scheduling information transmission and the data transmission, and the second scheduling information indicates a second timing offset between the second scheduling information transmission and the data transmission, and the first timing offset is different from the second timing offset.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present Application claims priority to and is a continuation of U.S.application Ser. No. 15/423,826, filed on Feb. 3, 2017, entitled “METHODAND APPARATUS FOR LATENCY REDUCTION OF DEVICE-TO-DEVICE (D2D) MESSAGE INA WIRELESS COMMUNICATION SYSTEM”, which claims the benefit of U.S.Provisional Patent Application Ser. No. 62/291,911 filed on Feb. 5,2016. The entire disclosure of U.S. application Ser. No. 15/423,826 andthe entire disclosure of U.S. Provisional Patent Application Ser. No.62/291,911 are incorporated herein in their entirety by reference.

FIELD

This disclosure generally relates to wireless communication networks,and more particularly, to a method and apparatus for latency reductionof device-to-device message in a wireless communication system.

BACKGROUND

With the rapid rise in demand for communication of large amounts of datato and from mobile communication devices, traditional mobile voicecommunication networks are evolving into networks that communicate withInternet Protocol (IP) data packets. Such IP data packet communicationcan provide users of mobile communication devices with voice over IP,multimedia, multicast and on-demand communication services.

An exemplary network structure is an Evolved Universal Terrestrial RadioAccess Network (E-UTRAN). The E-UTRAN system can provide high datathroughput in order to realize the above-noted voice over IP andmultimedia services. A new radio technology for the next generation(e.g., 5G) is currently being discussed by the 3GPP standardsorganization. Accordingly, changes to the current body of 3GPP standardare currently being submitted and considered to evolve and finalize the3GPP standard.

SUMMARY

A method and apparatus are disclosed for latency reduction ofdevice-to-device message in a wireless communication system. In oneembodiment, the method includes the UE receiving a grant on a firstinterface wherein the grant indicates resource for transmittingscheduling information and resources for data transmission on a secondinterface. The method also includes the UE transmitting a firstscheduling information on the second interface in a first specifictiming interval and transmits a second scheduling information on thesecond interface in a second specific timing interval, wherein thetiming difference between the second specific timing and the firstspecific timing is indicated by the grant, and wherein the firstscheduling information indicates a first timing offset between the firstscheduling information transmission and the data transmission, thesecond scheduling information indicates a second timing offset betweenthe second scheduling information transmission and the datatransmission, and the first timing offset is different from the secondtiming offset.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a diagram of a wireless communication system according toone exemplary embodiment.

FIG. 2 is a block diagram of a transmitter system (also known as accessnetwork) and a receiver system (also known as user equipment or UE)according to one exemplary embodiment.

FIG. 3 is a functional block diagram of a communication system accordingto one exemplary embodiment.

FIG. 4 is a functional block diagram of the program code of FIG. 3according to one exemplary embodiment.

FIG. 5 is a reproduction of Table 14.2-1 of 3GPP TS 36.213 V12.8.0.

FIG. 6 is a reproduction of FIG. 5 of 3GPP R1-156978.

FIG. 7 is a reproduction of FIG. 6 of 3GPP R1-156978.

FIG. 8 is a reproduction of FIG. 7 of 3GPP R1-156978.

FIG. 9 is a diagram according to one exemplary embodiment.

FIG. 10 is a diagram according to one exemplary embodiment.

FIG. 11 is a flow chart according to one exemplary embodiment.

FIG. 12 is a flow chart according to one exemplary embodiment.

DETAILED DESCRIPTION

The exemplary wireless communication systems and devices described belowemploy a wireless communication system, supporting a broadcast service.Wireless communication systems are widely deployed to provide varioustypes of communication such as voice, data, and so on. These systems maybe based on code division multiple access (CDMA), time division multipleaccess (TDMA), orthogonal frequency division multiple access (OFDMA),3GPP LTE (Long Term Evolution) wireless access, 3GPP LTE-A orLTE-Advanced (Long Term Evolution Advanced), 3GPP2 UMB (Ultra MobileBroadband), WiMax, or some other modulation techniques.

In particular, the exemplary wireless communication systems devicesdescribed below may be designed to support one or more standards such asthe standard offered by a consortium named “3rd Generation PartnershipProject” referred to herein as 3GPP, including: RP-152293, “New WIproposal: Support for V2V services based on LTE sidelink”, LGElectronics, Huawei, HiSilicon, CATT, CATR; TR 22.885 V14.0.0 (2015-12),“Study on LTE support for Vehicle to Everything (V2X) services (Release14)”; TS 36.213 V12.8.0 (2015-12), “E-UTRA: Physical layer procedures(Release 12)”; R1-156978, “System level consideration and evaluation forV2V communication”, Alcatel-Lucent Shanghai Bell, Alcatel-Lucent; and3GPP TS 36.321 V12.8.0 (2015-12), “E-UTRA: Medium Access Control (MAC)protocol specification (Release 12)”. The standards and documents listedabove are hereby expressly incorporated by reference in their entirety.

FIG. 1 shows a multiple access wireless communication system accordingto one embodiment of the invention. An access network 100 (AN) includesmultiple antenna groups, one including 104 and 106, another including108 and 110, and an additional including 112 and 114. In FIG. 1, onlytwo antennas are shown for each antenna group, however, more or fewerantennas may be utilized for each antenna group. Access terminal 116(AT) is in communication with antennas 112 and 114, where antennas 112and 114 transmit information to access terminal 116 over forward link120 and receive information from access terminal 116 over reverse link118. Access terminal (AT) 122 is in communication with antennas 106 and108, where antennas 106 and 108 transmit information to access terminal(AT) 122 over forward link 126 and receive information from accessterminal (AT) 122 over reverse link 124. In a FDD system, communicationlinks 118, 120, 124 and 126 may use different frequency forcommunication. For example, forward link 120 may use a differentfrequency then that used by reverse link 118.

Each group of antennas and/or the area in which they are designed tocommunicate is often referred to as a sector of the access network. Inthe embodiment, antenna groups each are designed to communicate toaccess terminals in a sector of the areas covered by access network 100.

In communication over forward links 120 and 126, the transmittingantennas of access network 100 may utilize beamforming in order toimprove the signal-to-noise ratio of forward links for the differentaccess terminals 116 and 122. Also, an access network using beamformingto transmit to access terminals scattered randomly through its coveragecauses less interference to access terminals in neighboring cells thanan access network transmitting through a single antenna to all itsaccess terminals.

An access network (AN) may be a fixed station or base station used forcommunicating with the terminals and may also be referred to as anaccess point, a Node B, a base station, an enhanced base station, anevolved Node B (eNB), or some other terminology. An access terminal (AT)may also be called user equipment (UE), a wireless communication device,terminal, access terminal or some other terminology.

FIG. 2 is a simplified block diagram of an embodiment of a transmittersystem 210 (also known as the access network) and a receiver system 250(also known as access terminal (AT) or user equipment (UE)) in a MIMOsystem 200. At the transmitter system 210, traffic data for a number ofdata streams is provided from a data source 212 to a transmit (TX) dataprocessor 214.

In one embodiment, each data stream is transmitted over a respectivetransmit antenna. TX data processor 214 formats, codes, and interleavesthe traffic data for each data stream based on a particular codingscheme selected for that data stream to provide coded data.

The coded data for each data stream may be multiplexed with pilot datausing OFDM techniques. The pilot data is typically a known data patternthat is processed in a known manner and may be used at the receiversystem to estimate the channel response. The multiplexed pilot and codeddata for each data stream is then modulated (i.e., symbol mapped) basedon a particular modulation scheme (e.g., BPSK, QPSK, M-PSK, or M-QAM)selected for that data stream to provide modulation symbols. The datarate, coding, and modulation for each data stream may be determined byinstructions performed by processor 230.

The modulation symbols for all data streams are then provided to a TXMIMO processor 220, which may further process the modulation symbols(e.g., for OFDM). TX MIMO processor 220 then provides N_(T) modulationsymbol streams to N_(T) transmitters (TMTR) 222 a through 222 t. Incertain embodiments, TX MIMO processor 220 applies beamforming weightsto the symbols of the data streams and to the antenna from which thesymbol is being transmitted.

Each transmitter 222 receives and processes a respective symbol streamto provide one or more analog signals, and further conditions (e.g.,amplifies, filters, and upconverts) the analog signals to provide amodulated signal suitable for transmission over the MIMO channel. N_(T)modulated signals from transmitters 222 a through 222 t are thentransmitted from N_(T) antennas 224 a through 224 t, respectively.

At receiver system 250, the transmitted modulated signals are receivedby N_(R) antennas 252 a through 252 r and the received signal from eachantenna 252 is provided to a respective receiver (RCVR) 254 a through254 r. Each receiver 254 conditions (e.g., filters, amplifies, anddownconverts) a respective received signal, digitizes the conditionedsignal to provide samples, and further processes the samples to providea corresponding “received” symbol stream.

An RX data processor 260 then receives and processes the N_(R) receivedsymbol streams from N_(R) receivers 254 based on a particular receiverprocessing technique to provide N_(T) “detected” symbol streams. The RXdata processor 260 then demodulates, deinterleaves, and decodes eachdetected symbol stream to recover the traffic data for the data stream.The processing by RX data processor 260 is complementary to thatperformed by TX MIMO processor 220 and TX data processor 214 attransmitter system 210.

A processor 270 periodically determines which pre-coding matrix to use(discussed below). Processor 270 formulates a reverse link messagecomprising a matrix index portion and a rank value portion.

The reverse link message may comprise various types of informationregarding the communication link and/or the received data stream. Thereverse link message is then processed by a TX data processor 238, whichalso receives traffic data for a number of data streams from a datasource 236, modulated by a modulator 280, conditioned by transmitters254 a through 254 r, and transmitted back to transmitter system 210.

At transmitter system 210, the modulated signals from receiver system250 are received by antennas 224, conditioned by receivers 222,demodulated by a demodulator 240, and processed by a RX data processor242 to extract the reserve link message transmitted by the receiversystem 250. Processor 230 then determines which pre-coding matrix to usefor determining the beamforming weights then processes the extractedmessage.

Turning to FIG. 3, this figure shows an alternative simplifiedfunctional block diagram of a communication device according to oneembodiment of the invention. As shown in FIG. 3, the communicationdevice 300 in a wireless communication system can be utilized forrealizing the UEs (or ATs) 116 and 122 in FIG. 1 or the base station (orAN) 100 in FIG. 1, and the wireless communications system is preferablythe LTE system. The communication device 300 may include an input device302, an output device 304, a control circuit 306, a central processingunit (CPU) 308, a memory 310, a program code 312, and a transceiver 314.The control circuit 306 executes the program code 312 in the memory 310through the CPU 308, thereby controlling an operation of thecommunications device 300. The communications device 300 can receivesignals input by a user through the input device 302, such as a keyboardor keypad, and can output images and sounds through the output device304, such as a monitor or speakers. The transceiver 314 is used toreceive and transmit wireless signals, delivering received signals tothe control circuit 306, and outputting signals generated by the controlcircuit 306 wirelessly. The communication device 300 in a wirelesscommunication system can also be utilized for realizing the AN 100 inFIG. 1.

FIG. 4 is a simplified block diagram of the program code 312 shown inFIG. 3 in accordance with one embodiment of the invention. In thisembodiment, the program code 312 includes an application layer 400, aLayer 3 portion 402, and a Layer 2 portion 404, and is coupled to aLayer 1 portion 406. The Layer 3 portion 402 generally performs radioresource control. The Layer 2 portion 404 generally performs linkcontrol. The Layer 1 portion 406 generally performs physicalconnections.

3GPP RP-152293 describes the work item for supporting V2V services basedon LTE sidelink as follows:

3 Justification

LTE-based V2X is urgently desired from market requirement as widelydeployed LTE-based network provides the opportunity for the vehicleindustry to realize the concept of ‘connected cars.’ The market for V2Vcommunication in particular is time sensitive because related activitiessuch as research projects, field test, and regulatory work are alreadyongoing or expected to start in some countries or regions such as US,Europe, Japan, Korea, and China. In July 2015, Ministry of Industry andInformation Technology (MIIT) of China approved Shanghai IntelligentConnected Vehicle Pilot Area from Shanghai International AutomobileCity. In October 2015, Shanghai International Automobile City releasedits initial plan to test 1000 LTE-V2X-enabled vehicles in an area of 90square kilometres in 2018-2019.3GPP is actively conducting study and specification work on LTE-basedV2X in order to respond to this situation. A SA1 work item was approvedin in SP-150573 to specify service requirements. SA2 agreed a study itemin S2-153532 to identify and evaluate potential architectureenhancements. In RAN #68, a study item on LTE-based V2X Services wasapproved in RP-151109. In this study PC5-based V2V has been givenhighest priority until RAN #70. The motivation for prioritizing V2Vuntil RAN #70 is to start a V2V work item in December 2015, as proposedin RP-151082. This RAN Feasibility Study (FS_LTE_V2X, TR 36.885) hascompleted the part of PC5 transport for V2V services. The RAN studyconcluded that it is feasible to support V2V services based on LTE PC5interface with necessary enhancements, and the study also recommended toenhance at least LTE sidelink resource allocation, physical layerstructure, and synchronization. In the meantime, the RAN study is alsoconsidering V2V operation scenarios based on not only LTE PC5 interfancebut also LTE Uu interfance or a combination of Uu and PC5, and themaximum efficiency of V2V services may be achieved byselecting/switching the operation scenario properly.Early completion of the corresponding RAN specification for PC5-basedV2V and integration with Uu interface will enable fast preparation fordevice and network implementation, thereby allowing more chance forLTE-based V2V in the market. In addition, it can provide the basis forother V2X services, especially V21/N and V2P services, so that RANsupport for all the V2X services can be completed in time.

4. Objective 4.1 Objective of SI or Core Part WI or Testing Part WI

The objectives of this work item are to specify LTE sidelinkenhancements for V2V services defied in [SA1 TR: TR 22.885].Specification work in this item should start from the relevant outcomeof the feasibility study on LTE-based V2X [RAN TR: TR 36.885].

As can be seen from TR 22.885, some V21 services have quite similarrequirements as V2V in terms of packet size, transmission frequency,latency requirement etc. This work item does not preclude some V21services be naturally supported with functionalities specified in thiswork item.The detailed objectives are as follows:

-   -   1) To specify enhancement to sidelink physical layer structure        necessary for V2V services [RAN1]    -   2) To specify enhancement to sidelink synchronization procedure        necessary for V2V services [RAN1, RAN2]        -   a) Low priority is given to enhancements to Rel-12/13            SLSS-based synchronization.    -   3) To identify what are necessary sidelink resource allocation        enhancement option(s) among the ones captured in TR 36.885 for        V2V services and specify the identified option(s) [RAN1, RAN2]    -   4) To specify a solution/requirement (if needed) for coexistence        of PC5-based V2V operation and legacy Uu operation with LTE in        the same carrier frequency [RAN1] and in an adjacent carrier        frequency [RAN4]    -   5) To specify a mechanism to enable E-UTRAN to select between        PC5 and Uu for transport of V2V messages within network        coverage, if necessary, in coordination with other working        groups [RAN2]        -   Note that this mechanism should be applicable to potential            enhancement to Uu for V2V services, e.g., the outcome of the            Uu-based V2V part in TR 36.885. Note that Uu performance            enhancentment for V2V is not the scope of this WI.    -   6) To specify necessary radio protocols and RRC signaling to        support the above features [RAN2]    -   7) To specify necessary radio access network protocols if        necessary [RAN3]    -   8) To develop a mechanism to prevent V2V from using spectrum        that V2V is not authorized to use [RAN2]    -   9) To specify UE Tx and Rx RF requirement covering operations at        up to 6 GHz carrier [RAN4]    -   10) To specify RRM core requirement [RAN4]        The work item should cover V2V services both with and without        LTE network coverage, and cover both the operating scenario        where the carrier(s) is/are dedicated to V2V services and the        operating scenario where the carrier(s) is/are licensed spectrum        and also used for normal LTE operation. This work should        consider extension to V21/V2P. This work should also consider        progress in SA WGs.        The specified enhancements should reuse the existing features of        LTE as much as possible.

3GPP TR 22.885 defines V2V and some possible use cases as follows:

4.2 Vehicle-to-Vehicle (V2V)

E-UTRAN allows such UEs that are in proximity of each other to exchangeV2V-related information using E-UTRA(N) when permission, authorisationand proximity criteria are fulfilled. The proximity criteria can beconfigured by the MNO. However, UEs supporting V2V Service can exchangesuch information when served by or not served by E-UTRAN which supportsV2X Service.The UE supporting V2V applications transmits application layerinformation (e.g. about its location, dynamics, and attributes as partof the V2V Service). The V2V payload must be flexible in order toaccommodate different information contents, and the information can betransmitted periodically according to a configuration provided by theMNO.V2V is predominantly broadcast-based; V2V includes the exchange ofV2V-related application information between distinct UEs directlyand/or, due to the limited direct communication range of V2V, theexchange of V2V-related application information between distinct UEs viainfrastructure supporting V2X Service, e.g., RSU, application server,etc.[ . . . ]

5.12 Pre-Crash Sensing Warning

5.12.1 Description

The pre-crash sensing warning application provides warnings to vehiclesin imminent and unavoidable collision by exchanging vehicles attributesafter non-avoidable crash is detected.

5.12.2 Pre-Conditions

Vehicle A and Vehicle B are supporting V2X Service and can communicatewith each other using V2V service.

5.12.3 Service Flows

Vehicle A detects that a crash cannot be avoided.

Vehicle A broadcasts a message with pre-crash warning information e.g.,vehicle attributes.

Vehicle B receives and processes the message and provides warnings ofpre-crash to driver.

5.12.4 Post-Conditions

The driver of Vehicle B takes appropriate action.

5.12.5 Potential Requirements

The following potential requirements are derived from this use case:

-   -   Note 1: Some example informative V2V parameter sets are offered        in Annex A of this document.        [PR.5.12.5-001] The E-UTRA(N) shall be able to transfer V2V        Service messages between two highly mobile UEs supporting V2V        Service with less than 20 ms latency and high reliability.    -   Note 2: This requirement might be treated with lower priority        compared to the other requirements.        [PR.5.12.5-002] The E-UTRA(N) shall be able to support UEs        supporting V2V Service moving in opposite directions at a        maximum absolute velocity of 160 km/h.        [PR.5.12.5-003] The E-UTRA(N) shall be able to support a message        size of up to [TBD] bytes.    -   Note 3: The content (which is out of scope of 3GPP) allows the        application layer to make decisions based on vehicles attributes        e.g. its current position, speed and acceleration.

3GPP TS 36.213 describes the Physical Sidelink Control Channel relatedprocedures on LTE sidelink as follows:

14.2 Physical Sidelink Control Channel Related Procedures

For sidelink transmission mode 1, if a UE is configured by higher layersto receive DCI format 5 with the CRC scrambled by the SL-RNTI, the UEshall decode the PDCCH/EPDCCH according to the combination defined inTable 14.2-1.

Table 14.2-1 of 3GPP TS 36.213 V12.8.0 is Reproduced as FIG. 5

14.2.1 UE Procedure for Transmitting the PSCCH

For sidelink transmission mode land PSCCH period i,

-   -   the UE shall determine the subframes and resource blocks for        transmitting SCI format 0 as follows.    -   SCI format 0 is transmitted in two subframes in the subframe        pool and one physical resource block per slot in each of the two        subframes, wherein the physical resource blocks belong to the        resource block pool, where the subframe pool and the resource        block pool are indicated by the PSCCH resource configuration (as        defined in subclause 14.2.3)    -   the two subframes and the resource blocks are determined using        “Resource for PSCCH” field (n_(PSCCH)) in the configured        sidelink grant (described in [8]) as described in subclause        14.2.1.1.    -   the UE shall set the contents of the SCI format 0 as follows:    -   the UE shall set the Modulation and coding scheme field        according to the Modulation and coding scheme indicated by the        higher layer parameter mcs-r12 if the parameter is configured by        higher layers.    -   the UE shall set the Frequency hopping flag according to the        “Frequency hopping flag” field in the configured sidelink grant.    -   the UE shall set the Resource block assignment and hopping        resource allocation according to the “Resource block assignment        and hopping resource allocation” field in the configured        sidelink grant.    -   the UE shall set the Time resource pattern according to the        “Time resource pattern” field in the configured sidelink grant.    -   the UE shall set the eleven-bit Timing advance indication to        I_(TAI)=└N_(TA)/16┘ to indicate sidelink reception timing        adjustment value using the N_(TA) (defined in [3]) value for the        UE in the subframe that is no earlier than subframe I_(b1)        ^(PSCCH)−4(I_(b1) ^(PSCCH) described in subclause 14.2.1.1).        For sidelink transmission mode 2,    -   SCI format 0 is transmitted in two subframes in the subframe        pool and one physical resource block per slot in each of the two        subframes, wherein the physical resource blocks belongs to the        resource block pool, where the subframe pool and the resource        block pool are indicated by the PSCCH resource configuration (as        defined in subclause 14.2.3)    -   the two subframes and the resource blocks are determined using        the procedure described in subclause 14.2.1.2    -   the UE shall set the eleven-bit Timing advance indication 4, in        the SCI format 0 to zero.        14.2.1.1 UE Procedure for Determining Subframes and Resource        Blocks for Transmitting PSCCH for Sidelink Transmission Mode 1        For 0≤n_(PSCCH)<└M_(RB) ^(PSCCH_RP)/2┘·L_(PSCCH),    -   one transmission of the PSCCH is in resource block m_(a1)        ^(PSCCH) of subframe l_(b1) ^(PSCCH) of the PSCCH period, where        a1=└n_(PSCCH)/L_(PSCCH)┘ and b1=n_(PSCCH) mod L_(PSCCH).    -   the other transmission of the PSCCH is in resource block m_(a2)        ^(PSCCH) of subframe l_(b2) ^(PSCCH) of the PSCCH period, where        a2=└n_(PSCCH)/L_(PSCCH)┘+└M_(RB) ^(PSCCH_RP)/2┘ and        b2=(n_(PSCCH)+1+└n_(PSCCH)/L_(PSCCH)┘ mod(L_(PSCCH)−1)) mod        L_(PSCCH).        where (l₀ ^(PSCCH), l₁ ^(PSCCH), . . . , l_(L) _(PSCCH) ⁻¹        ^(PSCCH)), (m₀ ^(PSCCH), m₁ ^(PSCCH), . . . , m_(M) _(RB)        _(PSCCH_RP) ⁻¹ ^(PSCCH)), L_(PSCCH) and M_(RB) ^(PSCCH_RP) are        described in subclause 14.2.3.        14.2.1.2 UE Procedure for Determining Subframes and Resource        Blocks for Transmitting PSCCH for Sidelink Transmission Mode 2        The allowed values for PSCCH resource selection are given by 0,        1 . . . (└M_(RB) ^(PSCCH_RP)/2┘·L_(PSCCH)−1) where L_(PSCCH) and        M_(RB) ^(PSCCH_RP) described in subclause 14.2.3. The two        subframes and the resource blocks are determined using selected        resource value n_(PSCCH) (described in [8]) and the procedure        described in subclause 14.2.1.1.        14.2.1.3 UE Procedure for PSCCH Power Control        For sidelink transmission mode 1 and PSCCH period i, the UE        transmit power P_(PSCCH) is given by the following    -   if the TPC command field in the configured sidelink grant        (described in [8]) for PSCCH period i is set to 0        P _(PSCCH) =P _(CMAX,PSCCH)    -   if the TPC command field in the configured sidelink grant        (described in [8]) for PSCCH period i is set to 1        P _(PSCCH)=min{P _(CMAX,PSCCH),10 log₁₀(M _(PSCCH))+P        _(O_PSCCH,1)+α_(PSCCH,1) ·PL} [dBm]        where P_(CMAX,PSCCH) is defined in [6], and M_(PSCCH)=1 and        PL=PL_(c) where PL_(c) is defined in subclause 5.1.1.1.        P_(O_PSCCH,1) and α_(PSCCH,1) are provided by higher layer        parameters p0-r12 and alpha-r12, respectively and are associated        with the corresponding PSCCH resource configuration.        For sidelink transmission mode 2, the UE transmit power        P_(PSCCH) is given by        P _(PSCCH)=min{P _(CMAX,PSCCH),10 log₁₀(M _(PSCCH))+P        _(O_PSCCH,2)+α_(PSCCH,2) ·PL} [dBm]        where P_(CMAX,PSCCH) is the P_(CMAX,c) configured by higher        layers and M_(PSCCH)=1 and PL=PL_(c) where PL_(c) is defined in        subclause 5.1.1.1. P_(O_PSCCH,2) and α_(PSCCH,2) are provided by        higher layer parameters p0-r12 and alpha-r12, respectively and        are associated with the corresponding PSCCH resource        configuration.        14.2.2 UE Procedure for Receiving the PSCCH        For each PSCCH resource configuration associated with sidelink        transmission mode 1, a UE configured by higher layers to detect        SCI format 0 on PSCCH shall attempt to decode the PSCCH        according to the PSCCH resource configuration, and using the        Group destination IDs indicated by higher layers.        For each PSCCH resource configuration associated with sidelink        transmission mode 2, a UE configured by higher layers to detect        SCI format 0 on PSCCH shall attempt to decode the PSCCH        according to the PSCCH resource configuration, and using the        Group destination IDs indicated by higher layers.        14.2.3 UE Procedure for Determining Resource Block Pool and        Subframe Pool for PSCCH        A PSCCH resource configuration for transmission/reception is        associated with a set of periodically occurring time-domain        periods (known as PSCCH periods). The i-th PSCCH period begins        at subframe with subframe index j_(begin)=O+i·P and ends in        subframe with subframe index j_(end) O+(i+1)·P−1, where    -   0≤j_(begin),j_(end)<10240,    -   the subframe index is relative to subframe #0 of the radio frame        corresponding to SFN 0 of the serving cell or DFN 0 (described        in [11]),    -   0 is the offsetIndicator-r12 indicated by the PSCCH resource        configuration,    -   P is the sc-Period-r12 indicated by the PSCCH resource        configuration.        For a PSCCH period, the UE determines a PSCCH pool consisting of        a subframe pool and a resource block pool as follows.    -   For TDD, if the parameter tdd-Config-r12 is indicated by the        PSCCH resource configuration, the TDD UL/DL configuration used        for determining the subframe pool is given by the parameter        tdd-Config-r12, otherwise, the TDD UL/DL configuration used for        determining the subframe pool is given by the UL/DL        configuration (i.e. parameter subframeAssignment) for the        serving cell.    -   The first N′ uplink subframes are denoted by (l₀, l₁, . . .        l_(N′−1)) arranged in increasing order of subframe index, where        N′ is the length of the bitmap subframeBitmap-r12 indicated by        the PSCCH resource configuration.    -   A subframe l_(j) (0≤j<N′) belongs to the subframe pool if        a_(j)=1,    -   where (a₀, a₁, a₂, . . . , a_(N-1)) is the bitmap        subframeBitmap-r12 indicated by the PSCCH resource        configuration. The subframes in the subframe pool are denoted by        (l₀ ^(PSCCH), l₁ ^(PSCCH), . . . , l_(L) _(PSCCH) ⁻¹ ^(PSCCH))        arranged in increasing order of subframe index and L_(PSCCH) is        the number of subframes in the subframe pool. A PRB with index q        (0≤q<N_(RB) ^(SL)) belongs to the resource block pool if        S1≤q<S1+M or if S2−M<q≤S2, where S1, S2, and M denote the        prb-Start-r12, prb-End-r12 and prb-Num-r12 indicated by the        PSCCH resource configuration respectively.    -   The resource blocks in the resource block pool are denoted by        (m₀ ^(PSCCH), m₁ ^(PSCCH), . . . , m_(M) _(RB) _(PSCCH_RB) ⁻¹        ^(PSCCH)) arranged in increasing order of resource block indices        and M_(RB) ^(PSCCH_RP) is the number of resource blocks in the        resource block pool.

3GPP TS 36.321 describes the LTE sidelink on MAC as follows:

3.1 Definitions

[ . . . ]

SC Period: Sidelink Control period, the time period consisting oftransmission of SCI and its corresponding data.

SCI: The Sidelink Control Information contains the sidelink schedulinginformation such as resource block assignment, modulation and codingscheme and Group Destination ID [5].

[ . . . ]

Sidelink: UE to UE interface for sidelink communication and sidelinkdiscovery. The sidelink corresponds to the PC5 interface as defined in[13].

Sidelink Discovery Gap for Reception: Time period during which the UEdoes not receive any channels in DL from any serving cell, except duringrandom access procedure.

Sidelink Discovery Gap for Transmission: Time period during which the UEprioritizes transmission of Sidelink discovery over transmission ofchannels in UL, if they occur in the same subframe, except during randomaccess procedure.

4.2.1 MAC Entities

E-UTRA defines two MAC entities; one in the UE and one in the E-UTRAN.These MAC entities handle the following transport channels:

[ . . . ]

-   -   Sidelink Broadcast Channel (SL-BCH);    -   Sidelink Discovery Channel (SL-DCH);    -   Sidelink Shared Channel (SL-SCH).

5.10 Semi-Persistent Scheduling

When Semi-Persistent Scheduling is enabled by RRC, the followinginformation is provided [8]:

-   -   Semi-Persistent Scheduling C-RNTI;    -   Uplink Semi-Persistent Scheduling interval        semiPersistSchedlntervalUL and number of empty transmissions        before implicit release implicitReleaseAfter, if Semi-Persistent        Scheduling is enabled for the uplink;    -   Whether twoIntervalsConfig is enabled or disabled for uplink,        only for TDD;    -   Downlink Semi-Persistent Scheduling interval        semiPersistSchedlntervalDL and number of configured HARQ        processes for Semi-Persistent Scheduling        numberOfConfSPS-Processes, if Semi-Persistent Scheduling is        enabled for the downlink;        When Semi-Persistent Scheduling for uplink or downlink is        disabled by RRC, the corresponding configured grant or        configured assignment shall be discarded.        Semi-Persistent Scheduling is supported on the SpCell only.        Semi-Persistent Scheduling is not supported for RN communication        with the E-UTRAN in combination with an RN subframe        configuration.    -   NOTE: When eIMTA is configured for the SpCell, if a configured        uplink grant or a configured downlink assignment occurs on a        subframe that can be reconfigured through eIMTA L1 signalling,        then the UE behaviour is left unspecified.

5.14 SL-SCH Data Transfer

5.14.1 SL-SCH Data Transmission

5.14.1.1 SL Grant Reception and SCI Transmission

In order to transmit on the SL-SCH the MAC entity must have at least onesidelink grant. Sidelink grants are selected as follows:

-   -   if the MAC entity is configured to receive a single sidelink        grant dynamically on the PDCCH and more data is available in        STCH than can be transmitted in the current SC period, the MAC        entity shall:        -   using the received sidelink grant determine the set of            subframes in which transmission of SCI and transmission of            first transport block occur according to subclause 14.2.1 of            [2];        -   consider the received sidelink grant to be a configured            sidelink grant occurring in those subframes starting at the            beginning of the first available SC Period which starts at            least 4 subframes after the subframe in which the sidelink            grant was received, overwriting a previously configured            sidelink grant occurring in the same SC period, if            available;        -   clear the configured sidelink grant at the end of the            corresponding SC Period;    -   else, if the MAC entity is configured by upper layers to receive        multiple sidelink grants dynamically on the PDCCH and more data        is available in STCH than can be transmitted in the current SC        period, the MAC entity shall for each received sidelink grant:        -   using the received sidelink grant determine the set of            subframes in which transmission of SCI and transmission of            first transport block occur according to subclause 14.2.1 of            [2];        -   consider the received sidelink grant to be a configured            sidelink grant occurring in those subframes starting at the            beginning of the first available SC Period which starts at            least 4 subframes after the subframe in which the sidelink            grant was received, overwriting a previously configured            sidelink grant received in the same subframe number but in a            different radio frame as this configured sidelink grant            occurring in the same SC period, if available;        -   clear the configured sidelink grant at the end of the            corresponding SC Period;    -   else, if the MAC entity is configured by upper layers to        transmit using one or multiple pool(s) of resources as indicated        in subclause 5.10.4 of [8] and more data is available in STCH        than can be transmitted in the current SC period, the MAC entity        shall for each sidelink grant to be selected:    -   [ . . . ]        -   NOTE: Retransmissions on SL-SCH cannot occur after the            configured sidelink grant has been cleared.        -   NOTE: If the MAC entity is configured by upper layers to            transmit using one or multiple pool(s) of resources as            indicated in subclause 5.10.4 of [8], it is left for UE            implementation how many sidelink grants to select within one            SC period taking the number of sidelink processes into            account.            The MAC entity shall for each subframe:    -   if the MAC entity has a configured sidelink grant occurring in        this subframe:        -   if the configured sidelink grant corresponds to transmission            of SCI:            -   instruct the physical layer to transmit SCI                corresponding to the configured sidelink grant.        -   else if the configured sidelink grant corresponds to            transmission of first transport block:            -   deliver the configured sidelink grant and the associated                HARQ information to the Sidelink HARQ Entity for this                subframe.            -   NOTE: If the MAC entity has multiple configured grants                occurring in one subframe and if not all of them can be                processed due to the single-cluster SC-FDM restriction,                it is left for UE implementation which one of these to                process according to the procedure above.                5.14.2 SL-SCH Data Reception                5.14.2.1 SCI Reception                SCI transmitted on the PSCCH indicate if there is a                transmission on SL-SCH and provide the relevant HARQ                information.                The MAC entity shall:    -   for each subframe during which the MAC entity monitors PSCCH:        -   if SCI for this subframe has been received on the PSCCH with            a Group Destination ID of interest to this MAC entity:            -   determine the set of subframes in which reception of the                first transport blocks occur according to subclause                14.2.2 of [2] using the received SCI;            -   store the SCI and associated HARQ information as SCI                valid for the subframes corresponding to first                transmission of each transport block;    -   for each subframe for which the MAC entity has a valid SCI:        -   deliver the SCI and the associated HARQ information to the            Sidelink HARQ Entity.

3GPP R1-156978 generally describes the frame structure for latencyreduction, especially considering for urgent messages, as follows:

Latency Reduction for Urgent Messages

The most strict latency requirement for V2X is 20 ms for the case ofpre-crash warning. The frame structure in FIG. 1 can't meet thisrequirement.

For latency reduction for urgent messages, separate SA resource poolsare allocated for V2V messages of different latency requirements. Asshown in FIG. 5, for periodic messages with 100 ms latency requirement,SA resource pool 1 and data resource pool 1 are allocated, which areTDMed. Data pool 1 follows SA pool 1 in time domain. For urgent messageswith 20 ms latency requirement, SA resource pool 2 and data resourcepool 2 are allocated, which are FDMed. FDM between SA pool 2 and datapool 2 increases occurrence frequency of SA resources in time domain toreduce SA transmission latency. Data pool 1 and data pool 2 areidentical. They share the same resources to accommodate dynamic trafficefficiently.

FIG. 5 of 3GPP R1-156978 is Reproduced as FIG. 6

From a UE Perspective, PSSCH Transmissions in Data Pool 2 Follow PSCCHTransmissions in SA Pool 2. After a UE with Urgent Message FinishesTransmitting PSCCHs, it Uses the Next Available Sub-Frames for PSSCHTransmissions.

For urgent messages with 20 ms latency requirement, an alternativescheme is that multiple SA resource pools with short duration areallocated sequentially, e.g. 4 SA pools (SA pool 2 to SA pool 5) in FIG.6. The same number of data resource pools is allocated accordingly. Eachdata pool follows its corresponding SA pool in time domain. For periodicmessages, data pool 1 is allocated, which comprises all data pools forurgent messages (e.g. data pool 3/4/5/2). Hence periodic messages andurgent messages share the same data resources to accommodate dynamictraffic efficiently.To further reduce latency for urgent messages, SA pool 1 can be dividedin to multiple parts, e.g. two parts in FIG. 6, spread in time domain.Accordingly, data pool 1 is divided into multiple parts. The associatedcost is the slightly increased latency for periodical messages. However,the 100 ms latency can still be met. For example in FIG. 6, the worstlatency increases from 80 ms (in FIG. 1) to 100 ms.

FIG. 6 of 3GPP R1-156978 is Reproduced as FIG. 7

To improve system level performance, multiple PSSCH transmissions (e.g.2 transmissions in FIG. 7) can be configured for a data MAC PDU.Considering urgent messages and periodic messages share the same dataresources, the time domain patterns of short span are reserved for PSSCHtransmissions of urgent messages.Further, to improve the reliability for transmissions of urgentmessages, a UE with periodic messages may mute its transmissions atsub-frames used by PSSCHs of urgent messages. It can reduce collisionsor in-band emission interference to PSSCHs of urgent messages.

FIG. 7 of 3GPP R1-156978 is Reproduced as FIG. 8

Proposal 4: Consider FDM Between SA and Data Resource Pools to Meet 20ms Latency Requirement.

Proposal 5: Consider the Frame Structure in FIG. 6 to Meet 20 ms LatencyRequirement.

The strictest latency requirement for V2X is 20 ms for the case ofpre-crash warning. The frame structure in D2D cannot meet thisrequirement. To reduce the latency of V2V (Vehicle-to-Vehicle) messagetransmission, there are some proposals, for instances shortening SCperiod, multiplexing SA pool with data pool in frequency domain. FIG. 7is an exemplary frame structure design for latency reduction provided in3GPP R1-156978. However, with the constraint of SA pool, the requiredtime from receiving a SL grant and transmitting an urgent message wouldbe at least (4+L_(SA)+T_(data)) ms, wherein 4 ms is assumed for a SLgrant before the starting of the associated SA pool, L_(SA) is the timelength of a SA pool, and T_(data) is the time of the first datatransmission after the end of the SA pool beforehand. If the time forrequesting SL grant is also considered, the latency would become longer.

In one embodiment, to further reduce the latency, fixed timing betweenSL grant and associated SA transmission could be applied. The UE doesnot require waiting for next SA pool after receiving SL grant. The fixedtiming may be specified or configured. As an example shown in FIG. 9,the SA transmission upon receiving SL grant 1 in the upper figurefollows the constraint of SA pool, and the SA transmission uponreceiving SL grant 2 in the lower figure follows fixed timing, X ms. Incomparison, the SA transmission associated to SL grant 2 can betransmitted faster than the SA transmission associated to SL grant1 (inthe casewhere SL grant 1 and SL grant 2 are considered to have beenreceived at the same time). The reduced latency is around 0˜L_(SA) msdepending on the timing when the SL grant was received.

Assuming SA repetition is required for reliability, the UE transmits atleast a first SA transmission, and a second SA transmission for areceived SL grant. Fixed timing may be applied between the SL grant andthe associated first SA transmission. For the timing occasion of thesecond SA transmission, there are some alternatives as follows:

-   1. Alternative 1—Based on the timing occasion of the first SA    (Scheduling Assignment) transmission, apply specific formula to    derive the timing occasion of the second SA transmission within the    same SA pool, which is generally similar to the current D2D    processing. Furthermore, the first SA transmission has the same    content as the second SA transmission. For this alternative, there    may or may not be a data pool division in the time domain.-   2. Alternative 2—A fixed timing is applied between the timing    occasion of the first SA transmission and the second SA    transmission. For instance, the timing occasion of the second SA    transmission is the next one subframe after the timing occasion of    the first SA transmission. Furthermore, the first SA transmission    has the same content as the second SA transmission. To help the    receiver to distinguish between the first SA transmission and the    second SA transmission, the timing occasion of the first SA    transmission can be fixed at even-index or odd-index subframe. In    one embodiment, the first SA transmission could utilize different    DMRS from the second SA transmission. More specifically, the    different DMRS means difference phases of a reference sequence. In    one embodiment, the first SA transmission and the second SA    transmission could be transmitted in different frequency resource    pools. The frequency resource pools are configured or specified. For    this alternative, there is no SA pool division in time domain, at    least for the SA resources multiplexed with data resources in    frequency domain. Furthermore, there may or may not be a data pool    division in the time domain.-   3. Alternative 3—The SL grant indicates the timing difference    between the timing occasion of the first SA transmission and the    second SA transmission. The first SA transmission has the different    content as the second SA transmission since the receiver side does    not know the timing difference beforehand. However, the first SA and    the second SA indicate the same resources for data transmission. For    instance, the first SA indicates a first timing offset between the    first SA and the first data transmission, and the second SA    indicates a second timing offset between the second SA and the first    data transmission. More specifically, the second timing offset can    be zero. For this alternative, there is no SA pool division in time    domain, at least for the SA resources multiplexed with data    resources in frequency domain. Furthermore, there may or may not be    a data pool division in the time domain.

FIG. 10 illustrates an example of the three alternatives for the timingof the second SA transmission. The first SA transmission upon receivingSL grant 1 follows the constraint of SA pool, and the first SAtransmission upon receiving SL grant 2-4 follows fixed timing, X ms. ForAlternative 1, the timing of the second SA transmission is derived froma specific formula based on the timing of the first SA transmission,wherein the first SA transmission and the second SA transmission arewith the same SA pool. For Alternative 2, the timing occasion of thesecond SA transmission is the next one subframe after the timingoccasion of the first SA transmission. For Alternative 3, the timingoccasion of the second SA transmission is the next Y-th subframe afterthe timing occasion of the first SA transmission, wherein Y is indicatedby SL grant 4. For the SA resources multiplexed with data resources inthe frequency domain, there is no SA pool division in the time domain ofAlternative 2 and Alternative 3.

FIG. 11 is a flow chart 1100 according to one exemplary embodiment fromthe perspective of a UE. In step 1105, the UE receives a grant on afirst interface wherein the grant indicates resource for transmittingscheduling information and resources for data transmission on a secondinterface.

In step 1110, the UE transmits a first scheduling information on thesecond interface in a first specific timing interval. In step 1115, theUE transmits a second scheduling information on the second interface ina second specific timing interval, wherein the timing difference betweenthe second specific timing and the first specific timing is indicated bythe grant, and wherein the first scheduling information indicates afirst timing offset between the first scheduling informationtransmission and the data transmission, the second schedulinginformation indicates a second timing offset between the secondscheduling information transmission and the data transmission, and thefirst timing offset is different from the second timing offset.Furthermore, the UE transmits the data transmission associated with boththe first scheduling information and the second scheduling informationon the second interface.

Referring back to FIGS. 3 and 4, in one exemplary embodiment of a UE,the device 300 includes a program code 312 stored in the memory 310program code 312. The CPU 308 could execute program code 312 to enablethe UE (i) to receive a grant on a first interface wherein the grantindicates resource for transmitting scheduling information and resourcesfor data transmission on a second interface, (ii) to transmit a firstscheduling information on the second interface in a first specifictiming interval, and (iii) to transmit a second scheduling informationon the second interface in a second specific timing interval, whereinthe timing difference between the second specific timing and the firstspecific timing is indicated by the grant, and wherein the firstscheduling information indicates a first timing offset between the firstscheduling information transmission and the data transmission, and thesecond scheduling information indicates a second timing offset betweenthe second scheduling information transmission and the datatransmission, and the first timing offset is different from the secondtiming offset. Furthermore, the CPU 308 can execute the program code 312to perform all of the above-described actions and steps or othersdescribed herein.

FIG. 12 is a flow chart 1200 according to one exemplary embodiment fromthe perspective of a UE. In step 1205, the UE receives a grant on afirst interface wherein the grant indicates resource for transmittingscheduling information and resources for data transmission on a secondinterface.

In step 1210, the UE transmits a first scheduling information on thesecond interface in a first specific timing interval. In step 1215, theUE transmits a second scheduling information on the second interface ina second specific timing interval. In step 1220, the UE transmits thedata transmission associated with both the first scheduling informationand the second scheduling information on the second interface, whereinthe timing difference between the second specific timing and the firstspecific timing is indicated by the grant, and wherein the firstscheduling information indicates a timing offset between the firstscheduling information transmission and the data transmission, and thesecond scheduling information is transmitted at the same timing as thedata transmission.

Referring back to FIGS. 3 and 4, in one exemplary embodiment of a UE,the device 300 includes a program code 312 stored in the memory 310program code 312. The CPU 308 could execute program code 312 to enablethe UE (i) to receive a grant on a first interface wherein the grantindicates resource for transmitting scheduling information and resourcesfor data transmission on a second interface, (ii) to transmit a firstscheduling information on the second interface in a first specifictiming interval, (iii) to transmit a second scheduling information onthe second interface in a second specific timing interval, and (iv) totransmit the data transmission associated with both the first schedulinginformation and the second scheduling information on the secondinterface, wherein the timing difference between the second specifictiming and the first specific timing is indicated by the grant, andwherein the first scheduling information indicates a timing offsetbetween the first scheduling information transmission and the datatransmission, and the second scheduling information is transmitted atthe same timing as the data transmission. Furthermore, the CPU 308 canexecute the program code 312 to perform all of the above-describedactions and steps or others described herein.

In one embodiment, the first interface could be a Uu interface or a PC5interface. In addition, the second interface could be a Uu interface ora PC5 interface. Furthermore, resources for transmission of schedulinginformation and resources for data transmission could be FDM (FrequencyDivision Multiplex). Resources for transmission of schedulinginformation could be multiplexed with resources for data transmission infrequency domain.

In one embodiment, the second timing offset could be zero. Furthermore,the first specific timing interval occurs at a fixed timing differenceafter the timing of receiving the grant, and the fixed timing differenceis specified or configured. Alternatively, the fixed timing differencecould be 4 TTIs (Transmission Time Intervals).

In one embodiment, resources available for the transmission of thescheduling information are divided into multiple resource pools in atime domain. Furthermore, the scheduling information in the firstspecific timing interval and scheduling information transmitted in asecond specific timing interval are associated with a same resource poolin the time domain.

In an alternative embodiment, resources available for the transmissionof the scheduling information are not divided into multiple resourcepools in a time domain at least for deriving the first specific timinginterval and the second specific timing interval. Furthermore, the grantcould indicate a timing difference between the second specific timinginterval and the first specific timing interval.

In one embodiment, resources available for the transmission of thescheduling information are divided into at least two resource parts in afrequency domain. Furthermore, the transmission of the schedulinginformation in the first specific timing interval is associated with oneresource part and the transmission of scheduling information in a secondspecific timing interval is associated with another resource part. Inaddition, the transmission of the scheduling information in the firstspecific timing interval could have different content than thetransmission of the scheduling information in the second specific timinginterval.

In one embodiment, the first scheduling information could indicate theresources for a data transmission on a second interface, and the secondscheduling information could indication the same resources for the datatransmission as the first scheduling information. Furthermore, the firstscheduling information could have different content than the secondscheduling information.

In one embodiment, resources available for data transmission are dividedinto multiple data resource pools in a time domain. Alternatively,resources available for data transmission are not divided into multipledata resource pools in a time domain.

Various aspects of the disclosure have been described above. It shouldbe apparent that the teachings herein may be embodied in a wide varietyof forms and that any specific structure, function, or both beingdisclosed herein is merely representative. Based on the teachings hereinone skilled in the art should appreciate that an aspect disclosed hereinmay be implemented independently of any other aspects and that two ormore of these aspects may be combined in various ways. For example, anapparatus may be implemented or a method may be practiced using anynumber of the aspects set forth herein. In addition, such an apparatusmay be implemented or such a method may be practiced using otherstructure, functionality, or structure and functionality in addition toor other than one or more of the aspects set forth herein. As an exampleof some of the above concepts, in some aspects concurrent channels maybe established based on pulse repetition frequencies. In some aspectsconcurrent channels may be established based on pulse position oroffsets. In some aspects concurrent channels may be established based ontime hopping sequences. In some aspects concurrent channels may beestablished based on pulse repetition frequencies, pulse positions oroffsets, and time hopping sequences.

Those of skill in the art would understand that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

Those of skill would further appreciate that the various illustrativelogical blocks, modules, processors, means, circuits, and algorithmsteps described in connection with the aspects disclosed herein may beimplemented as electronic hardware (e.g., a digital implementation, ananalog implementation, or a combination of the two, which may bedesigned using source coding or some other technique), various forms ofprogram or design code incorporating instructions (which may be referredto herein, for convenience, as “software” or a “software module”), orcombinations of both. To clearly illustrate this interchangeability ofhardware and software, various illustrative components, blocks, modules,circuits, and steps have been described above generally in terms oftheir functionality. Whether such functionality is implemented ashardware or software depends upon the particular application and designconstraints imposed on the overall system. Skilled artisans mayimplement the described functionality in varying ways for eachparticular application, but such implementation decisions should not beinterpreted as causing a departure from the scope of the presentdisclosure.

In addition, the various illustrative logical blocks, modules, andcircuits described in connection with the aspects disclosed herein maybe implemented within or performed by an integrated circuit (“IC”), anaccess terminal, or an access point. The IC may comprise a generalpurpose processor, a digital signal processor (DSP), an applicationspecific integrated circuit (ASIC), a field programmable gate array(FPGA) or other programmable logic device, discrete gate or transistorlogic, discrete hardware components, electrical components, opticalcomponents, mechanical components, or any combination thereof designedto perform the functions described herein, and may execute codes orinstructions that reside within the IC, outside of the IC, or both. Ageneral purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

It is understood that any specific order or hierarchy of steps in anydisclosed process is an example of a sample approach. Based upon designpreferences, it is understood that the specific order or hierarchy ofsteps in the processes may be rearranged while remaining within thescope of the present disclosure. The accompanying method claims presentelements of the various steps in a sample order, and are not meant to belimited to the specific order or hierarchy presented.

The steps of a method or algorithm described in connection with theaspects disclosed herein may be embodied directly in hardware, in asoftware module executed by a processor, or in a combination of the two.A software module (e.g., including executable instructions and relateddata) and other data may reside in a data memory such as RAM memory,flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a harddisk, a removable disk, a CD-ROM, or any other form of computer-readablestorage medium known in the art. A sample storage medium may be coupledto a machine such as, for example, a computer/processor (which may bereferred to herein, for convenience, as a “processor”) such theprocessor can read information (e.g., code) from and write informationto the storage medium. A sample storage medium may be integral to theprocessor. The processor and the storage medium may reside in an ASIC.The ASIC may reside in user equipment. In the alternative, the processorand the storage medium may reside as discrete components in userequipment. Moreover, in some aspects any suitable computer-programproduct may comprise a computer-readable medium comprising codesrelating to one or more of the aspects of the disclosure. In someaspects a computer program product may comprise packaging materials.

While the invention has been described in connection with variousaspects, it will be understood that the invention is capable of furthermodifications. This application is intended to cover any variations,uses or adaptation of the invention following, in general, theprinciples of the invention, and including such departures from thepresent disclosure as come within the known and customary practicewithin the art to which the invention pertains.

The invention claimed is:
 1. A method of a UE (User Equipment),comprising: the UE receives a grant on a first interface wherein thegrant indicates a first resource for transmission of a first schedulinginformation, a second resource for transmission of a second schedulinginformation, and a time and frequency resource for a data transmissionin a resource pool on a second interface; the UE transmits the firstscheduling information in the first resource indicated by the grant onthe second interface in a first timing interval; the UE transmits thesecond scheduling information in the second resource indicated by thegrant on the second interface in a second timing interval; and the UEtransmits the data transmission in the time and frequency resourceindicated by the grant on the second interface in a third timinginterval, wherein a timing difference between the second timing intervalin which the second scheduling information is transmitted in the secondresource indicated by the grant and the first timing interval in whichthe first scheduling information is transmitted in the first resourceindicated by the grant is indicated by the grant, wherein the secondscheduling information is different than the first schedulinginformation, wherein the first timing interval is a first TTI(Transmission Time Interval), wherein the second timing interval is asecond TTI, and wherein the third timing interval is a third TTI.
 2. Themethod of claim 1, wherein at least one of a second timing offsetbetween transmission of the second scheduling information in the secondtiming interval and transmission of the data transmission in the thirdtiming interval is zero, or a first timing offset between transmissionof the first scheduling information in the first timing interval andtransmission of the data transmission in the third timing interval isthe same as the timing difference.
 3. The method of claim 1, wherein thefirst interface is a Uu interface and the second interface is a PC5interface.
 4. The method of claim 1, wherein the second resource fortransmission of the second scheduling information is multiplexed withthe time and frequency resource for the data transmission in frequencydomain.
 5. The method of claim 1, at least one of wherein the firstscheduling information in the first timing interval and the secondscheduling information transmitted in a second timing interval areassociated with the same resource pool in time domain, or wherein thetransmission of the first scheduling information and the transmission ofthe second scheduling information are in the same resource pool.
 6. Themethod of claim 1, wherein the first resource for transmission of thefirst scheduling information and the second resource for the secondscheduling information are not divided into multiple resource pools intime domain at least for deriving the first timing interval and thesecond timing interval.
 7. The method of claim 1, wherein the firstresource for transmission of the first scheduling information ismultiplexed with the time and frequency resource for the datatransmission at least in frequency domain.
 8. The method of claim 1,wherein the first scheduling information indicates the time andfrequency resource for the data transmission on the second interface,and the second scheduling information indicates the same time andfrequency resource for the data transmission as the first schedulinginformation.
 9. The method of claim 1, wherein the first schedulinginformation has different content as the second scheduling information.10. The method of claim 1, wherein the time and frequency resource forthe data transmission is not divided into multiple resource pools intime domain.
 11. A method of a UE (User Equipment), comprising: the UEreceives a grant on a first interface wherein the grant indicates afirst resource for transmission of a first scheduling information, asecond resource for transmission of a second scheduling information, anda time and frequency resource for a data transmission in a resource poolon a second interface; the UE transmits the first scheduling informationin the first resource indicated by the grant on the second interface ina first timing interval; the UE transmits the second schedulinginformation in the second resource indicated by the grant on the secondinterface in a second timing interval; and the UE transmits the datatransmission in the time and frequency resource indicated by the granton the second interface, wherein a timing difference between the secondtiming interval in which the second scheduling information istransmitted in the second resource indicated by the grant and the firsttiming interval in which the first scheduling information is transmittedin the first resource indicated by the grant is indicated by the grant,wherein the second scheduling information is different than the firstscheduling information.
 12. The method of claim 11, wherein the firstinterface is a Uu interface and the second interface is a PC5 interface.13. The method of claim 11, wherein the second resource for transmissionof the second scheduling information is multiplexed with the time andfrequency resource for the data transmission in frequency domain. 14.The method of claim 11, at least one of wherein the first schedulinginformation in the first timing interval and the second schedulinginformation transmitted in a second timing interval are associated withthe same resource pool in time domain, or wherein the transmission ofthe first scheduling information and the transmission of the secondscheduling information are in the same resource pool.
 15. The method ofclaim 11, wherein a timing offset between transmission of the firstscheduling information in the first timing interval and transmission ofthe data transmission in the second timing interval is the same as thetiming difference.
 16. The method of claim 11, wherein the firstresource for transmission of the first scheduling information ismultiplexed with the time and frequency resource for the datatransmission at least in frequency domain.
 17. The method of claim 11,wherein the first scheduling information indicates the time andfrequency resource for the data transmission on the second interface,and the second scheduling information indicates the same time andfrequency resource for the data transmission as the first schedulinginformation.
 18. The method of claim 11, wherein the first schedulinginformation has different content as the second scheduling information.19. The method of claim 11, wherein the time and frequency resource forthe data transmission is not divided into multiple resource pools intime domain.
 20. A UE (User Equipment), comprising: a control circuit; aprocessor installed in the control circuit; and a memory installed inthe control circuit and operatively coupled to the processor; whereinthe processor is configured to execute a program code stored in thememory to: receive a grant on a first interface wherein the grantindicates a first resource for transmission of a first schedulinginformation, a second resource for transmission of a second schedulinginformation, and a time and frequency resource for a data transmissionin a resource pool on a second interface; transmit the first schedulinginformation in the first resource indicated by the grant on the secondinterface in a first timing interval; transmit the second schedulinginformation in the second resource indicated by the grant on the secondinterface in a second timing interval; and transmit the datatransmission in the time and frequency resource indicated by the granton the second interface, wherein a timing difference between the secondtiming interval and the first timing interval is indicated by the grant,wherein the first timing interval is a first TTI (Transmission TimeInterval), and wherein the second timing interval is a second TTI.